Rinderpest Antibodies Research Articles

RADIOIMMUNOASSAY FOR DETECTION OF ANTI-RINDERPEST ANTIBODIES IN CATTLES

Liquid Phase Radioimmunoassay (RIA) was developed to detect and measure anti-rinderpest immunoglobulins in field animals sera, within two hours. Rinderpest virus adapted on Vero cell line culture and antigen purified by treatment with Triton-Gentron 13 Butanol, and, labeled with I isotope, using chloramin T iodination method. 
 Comparative studies for detecting anti-rinderpest immunoglobulin in 80 calves sera samples, using the developed assay in parallel with virus neutralization test (VNT). The study showed 58.75 % agreement between the two methods. However, 71 % of seven months old, non-vaccinated calves showed anti rinderpest antibodies in their sera, also 81 % of 10 months old vaccinated calves were developed antibodies in their blood. 
 These results demonstrate the development of sensitive, specific and rapid quantitative / qualitative radioimmunoassay, necessary for screening the development of immunity against rinderpest in cattle.

Characterization of Antigenic Sites on the Rinderpest Virus N Protein Uusing Monoclonal Antibodies

The N protein of the rinderpest virus (RPV) was analyzed topologically and antigenically by using anti-N monoclonal antibodies (Mabs). Ten Mabs were raised against the N protein of the RPV. At least six non-overlapping antigenic sites (sites A-F) were delineated by competitive binding assays using biotinylated Mabs. Of them 5 sites (A, C, D, E and F) on the N protein were recognized by RPV-specific Mabs in ELISA and IFA while site B was recognized by Mabs reacting with both RPV and PPRV. Non- reciprocal competition was found among sites C, D and E. Recombinant RPV N protein after exposure to 0.2% SDS exhibited higher ELISA titers in all Mabs recognizing 6 sites. Four sites (A, B, E and F) on 2% SDS-treated N protein lost completely reactivity with Mabs while the remaining sites (C and D) on the protein retained their antigenicity to some degree. It indicates that two sites (C and D) were sequential. Six representative Mabs bound to each site exhibited competition with rinderpest antibodies in a blocking ELISA, indicating that the sites were actively involved in antigenicity in cattle.

Rinderpest antibody detected in sheep and goats before an outbreak of rinderpest reported in cattle in northern Tanzania.

In January 1997, serum samples from 1346 adult sheep and goats were tested by a competitive ELISA to determine the prevalence of rinderpest in the northern zone of Tanzania. Seroconversion rates of 20%, 13%, 9%, 7% and 3% in sheep and goats were recorded in Ngorongoro, Monduli, Hai, Arumeru and Simanjiro districts, respectively. The low profile and insidious nature of the rinderpest virus involved caused very mild disease in cattle in some of these area. The mild signs associated with this outbreak of rinderpest resulted in difficulty in its diagnosis. In these circumstances, the presence of rinderpest antibody in sheep and goats served as a valuable and effective indicator of the rinderpest outbreak in cattle.

Seroepidemiology of rinderpest in bovids in Sri Lanka using the enzyme linked immunosorbent assay (ELISA) technique

Approximately 0.2% ( n=4397) of the bovids (cattle and buffalo) in Sri Lanka were sampled, from June 1992 using a multi-stage sampling procedure. Serum antibodies for the rinderpest virus were detected using the competitive enzyme-linked immunosorbent assay. The age, the agroclimatic zone, the management system practiced in the farms, and the vaccination history of the sampled bovids were studied as potential risk factors for being seropositive. The prevalence of rinderpest antibodies in non-vaccinated bovids was 3.5% ( n=4101). The prevalence was higher in the dry zone (9%; where the outbreak emerged in 1987), compared to bovids in the other zones (1%). Seropositive bovids over three years of age were approximately at fourfold higher chances of being seropositive compared to those that were ≤3 years old. The higher prevalence in older animals is probably due to exposure to the virus during the 1987 epidemic. Bovids from the dry zone (annual rainfall 20 to 35 inches) were at higher odds of being seropositive even after controlling for the possible effects of age, agroclimatic zone, management system and vaccination. The fact that 62% of bovids from the dry zone in this study were reared under extensive management system (free grazing) which allow unrestricted contact between animals, may be the reason for the above finding. A relatively poor response to vaccination observed in vaccinated bovids (seroprevalence=12%; n=296) could be attributed to difficulties in maintaining the vaccine at recommended temperatures in the field. This is the first island-wide study on seroprevalence of rinderpest in Sri Lanka.

Comparative ethnoveterinary and serological evaluation of the Karimojong Community Animal Health Worker Program in Uganda.

The Karimojong CAHW program, in which members of the pastoral Karimojong community were trained as basic veterinary care providers, was evaluated using ethnoveterinary techniques. A serological study of rinderpest antibody titers was also completed to compare serological results with ethnoveterinary results in the case of one disease, rinderpest. An outbreak of rinderpest-like disease that occurred during the field phase of the study was also investigated. The results show that rinderpest does exist in Karamoja in an apparently endemic form. Given the significant value placed by Karimojong herders on vaccinated animals, it can be concluded that they would adequately vaccinate their herds if they could trust the vaccine and the vaccinator. Discrepancies between ethnoveterinary and serological results show that ethnoveterinary techniques do not provide numerically accurate data concerning protection from disease, but that they can, nonetheless, provide basic, cost effective indications of disease patterns.

Use of dot-immunobinding assay for visual detection of rinderpest antibodies in vaccinated cattle.

A dot-immunobinding (DIB) assay was used to detect rinderpest antibodies in cattle vaccinated with Kabete 'O' strain vaccine, using purified rinderpest virus. Of 120 serum samples from vaccinated and non-vaccinated animals, rinderpest antibodies were detected in 80%, 88.4% and 91.6% of samples at 2, 3 and 4 weeks postvaccination respectively. All the serum samples from non-vaccinated animals were negative. The DIB results had a good correlation with those of the micro neutralisation test. The technique is simple, easy to perform and suitable for routine use in detecting rinderpest antibodies following vaccination.

Point seroprevalence of rinderpest antibody in cattle in Bangladesh

A serological point prevalence survey for rinderpest (RP) antibody was carried out on 1337 cattle from 20 locations in Bangladesh between March 1987 and April 1988. The seroprevalence was 8.5% but varied from 0 to 36%, depending upon the area from which cattle were sampled. Additionally, there was a significantly ( P<0.01) higher number of seropositive animals in cattle over 3 years of age than in cattle between 3 months and 3 years of age. The importance of the results in relation to national and regional rinderpest control programmes is discussed. If seronegativity indicates susceptibility, these results show that the immune status of the national herd is inadequate to prevent a major epidemic.

Dipstick enzyme immunoassay for rinderpest antibody in cattle

A dipstick enzyme immunoassay (ELISA) has been standardized for the detection of rinderpest antibodies. One hundred and thirty bovine serum samples were analysed by the dipstick ELISA method and the results compared with the conventional plate ELISA method. The sensitivity was found to be similar in both methods. The dipstick ELISA does not require expensive micro-plates and an ELISA reader, and is recommended for use in field laboratories where the qualitative detection of rinderpest antibodies is required.

Persistence of rinderpest maternal antibodies in lambs

Rinderpest antibodies in 166 lambs of different ages, born to vaccinated ewes were studied with avidin-biotin enzyme-linked immunosorbent assay. The mean serum background optical density (OD) value in 20 colostrum deprived lambs and 50 unvaccinated adult sheep was 0.12. The OD values of 166 one to six month-old colostrum-fed lambs ranged from 0.08 to 0.64 and the pooled rinderpest positive serum was 1.44. A peak value of 0.64 was obtained in the first week which gradually declined to become negative for the presence of rinderpest maternal antibodies at around six months of age (OD=< 0.24). Primary vaccination of lambs of vaccinated ewes is therefore considered appropriate at six months of age for effective immunisation with least interference of maternally-derived antibodies.

A competitive ELISA using anti-N monoclonal antibodies for specific detection of rinderpest antibodies in cattle and small ruminants

A competitive ELISA (C-ELISA) using monoclonal antibodies (mAbs) which bind to the nucleoprotein (NP) of rinderpest virus (RPV) for detection of RPV antibodies in cattle and small ruminant sera is described. Unlike virus neutralisation test (VNT), this test using mAb IVB2-4, can detect specific RPV antibodiesv without showing a cross-reaction with antibodies to peste-des-petits ruminants-virus (PPRV); by contrast, when mAb VE4-1 is used the test detects both RPV and PPRV antibodies, including low levels of antibodies that can be found in sera containing maternal antibodies. Although antibodies to the PPRV 75-1 strain are also detected with mAb 51-5-6, the test is suitable for assessing the immune status of cattle against the Rinderpest Old Kabete (RBOK) strain. The results from a panel of sera with a known status of vaccination provide evidence for a highly significant correlation between C-ELISA and VNT. This test may be a useful tool for a standardized and accurate determination of the immunity status of both cattle and small ruminants.

Analyses of baseline survey data on rinderpest in bahr el ghazal province, with proposal of an improved vaccination strategy against rinderpest for southern Sudan

Results from analyses of baseline surveillance data on rinderpest are used for proposing an improved vaccination strategy against rinderpest in southern Sudan. Sera from 4,074 (47%) of the total sample of 8,565 cattle collected in a series of cross-sectional surveys in 400 cattle camps in the Bahr el Ghazal Province of southern Sudan were tested for rinderpest antibodies using the standard virus neutralisation test (VNT) technique: 77.4% were positive while 22.6% gave negative results. The data were cross-classified according to five variables: herd management, breed, age, sex and geographic region (grazing location). The percentage antibody-positivity level (taken as an approximation of past experience with rinderpest antigen and the corresponding prevalence ratio estimates of relative risk) for each variable are discussed within the context of the known characteristics of immunity to rinderpest in endemic areas and the husbandry practices of the cattle owners in the study area. Results suggest that rinderpest "hot-spots" of transmission and/or low level of herd immunity should be mapped out for concentrated efforts to vaccinate calves and young adults so that the high level of antibody-positivity observed in this study can be maintained and transmission permanently interrupted.

A serological survey of rinderpest antibody in wildlife and sheep and goats in Northern Tanzania

An extensive serological survey for rinderpest antibody in wildlife, principally buffalo (Syncerus caffer), and sheep and goats has been undertaken in the previously endemic region of Northern Tanzania to determine whether or not the virus has continued to cycle in susceptible species since the last occurrence of overt disease in 1982. The results show that infection but not disease has occurred at least until 1987 in buffalo in parts of the Serengeti National Park but not in the other game areas of Tanzania where samples were taken. Sero-positive sheep and goats were widely distributed and have been found in 10 of the 14 districts sampled but there have been no reports of disease. These findings bring into question the possibility of eradicating the disease from Africa and continuous annual monitoring of this and other similar ecological zones will be required.

Investigations of rinderpest antibody in East African Wildlife, 1967-1971.

Buffaloes showed no material evidence of infection in W. Uganda (1/77 positive) but the disease probably occurred in E. Kenya in 1969/70. In the Serengeti area of Tanzania one batch of sera collected in August 1969 showed low antibody titre (10 or less) in 7 of 15 animals 2 to 5 years old. This activity was restricted both geographically and temporally, as well as being difficult to assay in tube neutralisation tests.

Simple and rapid dot-enzyme immunoassay for visual detection of rinderpest antibodies in bovine and caprine sera.

A modified solid phase enzyme immunoassay (EIA) is described for visual detection of anti-rinderpest virus (RPV) antibodies in cattle and goat sera. Dots of RPV antigens were adsorbed to nitrocellulose (NC) paper (hence Dot-EIA) and the adsorptive reactive sites were blocked with skim milk powder. After immersion in bovine or caprine test serum bound antibodies were reacted with a peroxidase-conjugated anti-bovine or anti-caprine IgG (H & L), respectively. Positive reactions were easily visualized as red-brown dots after enzyme degradation of a substrate containing hydrogen peroxide and amino-ethylcarbazole (AEC). The Dot-EIA was comparable to the serum neutralisation (SN) test in its ability to detect antibody in bovine sera seven or ten days after experimental infection (DPI) with live attenuated Kabete "O" (RBOK) strain of RPV (grown in Vero cells) by a combination of subcutaneous (s/c), intravenous (i/v) or intranasal (i/n) routes. Early (seven DPI) RPV antibodies were detected in a serum sample from one goat experimentally infected with RPV by combined s/c-i/v routes but not in another goat only infected intranasally. The specificity of the Dot-EIA was equal to that of the SN test, as serum samples, collected from these experimental animals and those inoculated with non infected Vero cell culture fluid, with SN titres of 0.3 or lower were all negative by Dot-EIA. The Dot-EIA may have potential application as a rapid, simple and economical field test in diagnosis of rinderpest, vaccination surveillance and other seroepidemiological studies.

Congenital Infection of Cattle with the Herpesvirus Causing Malignant Catarrhal Fever

Summary Nine pregnant cows, which were infected with malignant catarrhal fever virus (MCFV) in late pregnancy, developed the acute disease but virus was not demonstrable in their foetuses 5 to 10 days after onset. Two further cows, which recovered from the experimental disease, produced uninfected calves 2 to 8 months later. A third animal gave birth to 2 calves 14 and 22 months after recovery and both of these showed a delayed reaction to challenge at the age of 31 and 7 weeks respectively. One cow produced her third calf 44 months after inapparent infection with MCFV; thyroid monolayers prepared from this calf developed extensive cytopathic effects which were shown to be due to MCFV of undiminished virulence. The same cow gave birth to 3 further calves, the last being born 80 months after initial infection. All these were shown to be infected with MCFV, one being born with the disease, whereas another did not develop clinical signs of MCF until the age of 17 weeks. The behaviour of passively-acquired neutralizing antibody to MCF and rinderpest viruses was investigated in 2 calves. Antibody to MCFV was partially sensitive to 2-ME treatment and probably had a half-life of 7 to 8 days, whereas rinderpest antibody was catabolized 3 to 5 times more slowly and was not sensitive to 2-ME. It is suggested that the former may have been of the IgG1 class. Colostral antibody did not protect congenitally-infected calves against virus multiplication.

Studies on the epizootiology of rinderpest in blue wildebeest and other game species of northern Tanzania and southern Kenya, 1965-7.

A serum neutralization test was used to determine the incidence of rinderpest antibodies in populations of blue wildebeest (Connochaetes taurinus albojubatusThomas) occurring in the Serengeti-Mara districts of N. Tanzania and S. Kenya. By correlating the age of animals at the time of shooting with the presence or absence of antibodies it was possible to outline the course of rinderpest in these animals over the period 1961–7.Serengeti migrant wildebeest were extensively infected in 1961, but not in 1962 or any subsequent year. No samples have been collected from this group since mid-1966. Kirawira resident wildebeest were last infected in 1961 according to samples collected in February 1967. Two of 13 animals born into the Mara resident population in late 1961 or early 1962 were found to possess antibodies, together with a high proportion (74%) of animals born in early 1961. This finding was considered indicative of a rinderpest epizootic in this group in the terminal weeks of 1961. No subsequent infection occurred in Mara wildebeest between 1962 and March 1966. Ngorongoro resident wildebeest were infected in the second half of 1962 but have remained free of rinderpest from 1963 until at least April 1966.The findings of the present survey were compared and contrasted with results of a similar study carried out some 2 to 3 years previously.Field strains of bovine rinderpest virus were isolated from the Loliondo district of N. Tanzania in November 1965 and March 1966. Serum samples from buffalo, eland, impala, warthog, and resident wildebeest which inhabited areas adjoining the two outbreaks failed to provide evidence of any recent epizootic in game animals. Circumstantial evidence indicated that the virus could have persisted in the Loliondo area since 1961. Two resident wildebeest born in 1963 and 1964 respectively, were thought to have been infected during a period when the disease went unrecognised. Serengeti migrant wildebeest were not found to have been infected after a period of potential contact with sick cattle in March 1966.

Investigations on the incidence of rinderpest virus infection in game animals of N. Tanganyika and S. Kenya 1960/63

The incidence of rinderpest infection in game animals in selected localities of South Kenya and North Tanganyika was studied during the period 1960 to 1963. Serum samples from 590 wildebeest (Connochaetes taurinus), 48 eland (Taurotragus oryx), 65 Thompson's gazelle (Gazella thompsoni) and 39 Grant's gazelle (Gazella granti) were tested for rinderpest neutralizing antibody.Rinderpest infection was shown to have been very frequent in yearling wilde-beest in the Mara area of Kenya in 1959/60, in the Serengeti National Park of Tanganyika in late 1960 and also in the Serengeti, and some adjacent areas, during the latter half of 1961. In the Ngorongoro Crater in 1961 infection was far less widespread, with only 11% of the yearlings acquiring antibody, compared to 67% in the Serengeti. The infections in 1959 and 1960 were clinical epizootics, accompanied by a considerable mortality, whereas no overt disease was reported in the course of 1961. Eland were affected in a similar manner to wildebeest up to 1960 but only a low rate of serological conversion was demonstrated in 1961. Adult Thompson's gazelle showed a low rate (ca. 12%) of infection but no anti-body was detected in Grant's gazelle.Only a small proportion of the wildebeest calves born in early 1962 acquired antibody by mid-1963 and this was due, at least in part, to infection late in 1962; it was not clear, unfortunately, whether the positive animals belonged entirely to resident, as opposed to migratory, groups. No clinical signs or mortality were reported in this year.A low incidence of rinderpest infection in wildebeest was also demonstrated both before and after 1960 in the Kajiado district of Kenya, where disease of game has not been reported in recent years. It is possible that the positive animals, as also the 1962 cases in Tanganyika, acquired the virus from low-grade infections of cattle.The transmission of rinderpest antibody from wildebeest dam to calf, presumably via the colostrum, was demonstrated regularly, except in six calves about 1–2 weeks old. No completely satisfactory explanation was obtained for their failure to acquire passive antibody but it may have been due to abnormal disturbance in the herds, associated with the shooting. The antibody titres in calves were initially higher than those in the serum of their dams but by the end of the 3rd month this position had been reversed. Individual calves became serologically negative from about the 10th week of life and all were devoid of antibody by the 6th to 7th month. The half-life of passively-acquired antibody was 4·4 weeks.

Malignant Catarrhal Fever in East Africa: III.—Neutralizing Antibody in Free-living Wildebeest

SUMMARY Serum samples from 181 East African wildebeest were inactivated at 56°C. for 30 min. and examined for neutralizing activity against the virus of malignant catarrhal fever (MCF or snotsiekte). All animals over the age of 7 months were serologically positive and the mean SN50 titre for those aged 3 years or more was 10-1·70. Half of 12 calves in the birth to 4 weeks age group possessed high-titre antibody, presumably acquired from the colostrum of their dam. The other 6 had no antibody, although their mother’s serum contained the usual quantities; the normal transmission of rinderpest antibodies, from dam to offspring, also did not occur in these instances. No explanation was found for the failure, which was probably limited to animals in this age group. The mean antibody titre fell continuously during the second to fourth months of life, but then increased steadily from a minimum of 10-1·19 to a peak of 10-2·29, in animals 13 to 18 months old. In the great majority of calves there was no period when passively-acquired antibody had reached very low levels and active “immunization” had yet to take place. Viraemia was detected in 12 of 43 animals aged from one to 20 weeks and 11 of them had circulating antibody at the time of sampling; yearlings and adults which were viraemic also had antibody in their serum. It was concluded that colostral antibody did not interfere significantly with active infection and the establishment of a permanent “immune” state. Although some wildebeest are probably infected congenitally with MCF virus, immunological tolerance does not develop to this agent.

The Occurrence of Rinderpest Antibodies in the Sera of Sheep and Goats in Northern Nigeria

SUMMARY During a survey for rinderpest neutralizing antibodies in Northern Nigeria, using a neutralization test in tissue cultures, it was found that 18·8% of 642 sheep sera, and 15·2% of 1,472 goat sera contained antibodies. The agent causing these antibodies was probably endemic in the sheep and goat population and presumably had been for some years. In 420 goats tested, the correlation between the presence of antibodies and the absence of thermal response after caprinised rinderpest virus vaccine inoculation, although significant, was not so markedly significant as in cattle. From experiments, and literature survey, the conclusion was drawn that rinderpest virus in the living vaccines used in Nigeria had not spread from cattle to sheep and goats. The percentage of sheep with antibodies increased after natural contact with rinderpest-infected cattle. Nevertheless, direct contact of sheep and goats with rinderpest-infected cattle-was not considered to be the only cause of the antibodies found in the survey.

An Indirect Gel Diffusion Precipitation Test for the Detection of Rinderpest Antibody in Convalescent Cattle

Antibodies in the sera of rinderpest-convalescent cattle were readily detected by an indirect gel diffusion precipitation test. Such antibodies were not present in the sera of rinderpest-susceptible cattle. The antibodies differed from neutralizing antibodies and an apparent correlation existed between the development of antibody and the severity of the clinical reaction.